Advanced Symptoms in Diabetics Mitigates Early Benefits of Coronary Artery Bypass Grafting: Analysis of Over 10,000 Patients

Objectives: Coronary artery bypass grafting (CABG) is the preferred revascularisation option for diabetics with multivessel coronary artery disease, in current guideline recommendations. Not infrequently, coronary artery disease causes minimal symptoms in diabetic patients, so they present late for surgery and this could have implications for clinical outcomes. We sought to examine differences in symptom severity between diabetics and non-diabetics at presentation for CABG, and the impact on in-hospital outcomes. Methods: We retrieved prospectively collected data for all patients who had CABG between January 2000 and December 2022. Perioperative variables were compared between diabetic and non-diabetics. The association between in-hospital major adverse cardiac and cerebrovascular events (MACCE) and perioperative variables was determined using multivariate analysis. Results: Of 10,834 patients, diabetics constituted 24.8% (n = 2687) with mean age 66.4 ± 8.7 years compared to non-diabetics 65.9 ± 9.4, p = 0.02. More diabetics (p < 0.001) had unstable symptoms (31% vs 25%), heart failure (15.5% vs 8.5%), previous myocardial infarction (54.2% vs 46.2%), prior coronary stenting (19% vs 15.8%), left ventricular systolic ejection fraction < 0.5 (33.8% vs 23.8%), triple vessel coronary disease (73.8% vs 70%) and frequently underwent non-elective CABG (32.3% vs 27.6%). Operative mortality (2.3% vs 1.5%, p = 0.004) and MACCE rates (4.7% vs 2.9%, p < 0.001) were higher in diabetics. Diabetes, however, was not an independent predictor of MACCE, but non-elective operation (HR1.4, 95% CI 1.11 - 1.77, p < 0.001) and NYHA class III/IV (HR1.03, 95% CI 1.32 - 1.70, p = 0.03) were. Conclusions: Diabetics more often presented for non-elective CABG with advanced symptoms, impaired left ventricular function, prior myocardial infarction and coronary stenting. Advanced symptoms contributed to higher MACCE rates in diabetics. Diabetic patients should be referred early for surgery.